Dreamliner Probes Intensify

Twin Investigations of Jet's Batteries Show Signs of Diverging

International investigations into the battery malfunctions that grounded Boeing Co.'s 787 jet are accelerating, with U.S. and Japanese experts pursuing some new and possibly differing leads.

One facet of the effort led by experts from Tokyo appears to concentrate heavily on potential problems with the batteries themselves, while their counterparts in the U.S. seem more centered on possible hazards stemming from the manner in which...